The present invention is directed to a g-force trainer or centrifuge wherein a pilot is seated in a gondola mounted on an arm and subjected to g forces approximating those the pilot would encounter in a real aircraft. In today's high speed, highly maneuverable jet aircraft used in the military, a pilot is likely to be subjected to extremely high g forces and onset rates. The pilot must be trained to tolerate "g.sub.z " forces from approximately 3 gs to 9 gs and g.sub.z onset rates as high as 6 g/sec or more.
It has been found that the arm for a g-force trainer should have a length of approximately 20 feet or more to minimize inducing pilot disorientation during arm acceleration or deceleration. With this in mind, a g-force trainer having a massive arm approaching 50 feet in length has been proposed. Such a trainer tends to minimize inducing pilot disorientation but, due to excessive arm weight, requires an inordinately large power plant having for example a maximum output of approximately 16,000 HP. A g-force trainer having an arm length of approximately 16 feet has also been proposed to reduce the power demands on the motor. However, due to the arm length, induced pilot disorientation is possible during arm acceleration or deceleration; and a drive motor having a maximum output of approximately 1,000 horsepower is still required.
In designing a g-force trainer, then, one is faced with the problem of designing the arm so that it is long enough to minimize inducing pilot disorientation during arm acceleration or deceleration yet sufficiently lightweight to enable the use of a drive motor having relatively low horsepower output. Present approaches to the design of g-force trainers known to us have been unable to minimize inducing pilot disorientation while at the same time reducing power demands so that relatively small motors, e.g., motors having less than 1,000 hp maximum output, can be utilized to drive the arm.
Regardless of its weight, the arm must also be relatively stiff so as to minimize deflection under loading by the gondola and pilot. Also, the natural frequency of the arm should be in excess of approximately 3-6 hz, i.e., the natural frequency of the human body. For loss of consciousness (loc) training, the arm should be sufficiently lightweight so as to achieve the accelerations and decelerations required to subject the pilot to g.sub.z forces from approximately 3 gs to 9 gs. Since the human heart is able to pump blood at a force of approximately 4.2 gs, g.sub.z forces of approximately 4.2 gs or more will overcome the pumping ability of the heart and result in loss of consciousness.
To be truly effective, a g force trainer should not only be capable of subjecting the pilot to the foregoing range of g.sub.z forces and onset rates but should also permit the pilot to "execute" maneuvers which are expected to result in those forces and onset rates. Thus, a pilot is likely to encounter specific g.sub.z forces and onset rates when tracking a target aircraft practicing an evasive maneuver or when himself practicing an evasive maneuver to avoid a missile locked on the pilot's aircraft. Merely subjecting the pilot to a range of g.sub.z forces and onset rates without permitting the pilot to participate by "tracking" a target or "evading" a missile does not produce realistic g.sub.z force tolerance training.
During g.sub.z force training, moreover, it is desirable to visually monitor the pilot and to measure certain physiologic responses of the pilot such as heart rate, noninvasive blood pressure, skin temperature electrocardiogram, electromyogram, electroencephalogram and temporal pulse rate. The pilot's appearance and the electrocardiogram, electromyogram and electroencephalogram and temporal pulse measurements in particular should be displayed in real time for research purposes so that the pilot's condition can be monitored instantaneously during training. Any adverse or dangerous conditions should be noted immediately so that the trainer can be stopped if warranted.
Due to conventional wiring requirements, which result in low signal to noise ratios, the accuracy with which such physiologic measurements are recorded and displayed may be unacceptable. There is a need to minimize electrical noise whatever wire lengths are employed to ensure that such measurements are accurately recorded and displayed.
For military pilots, there are certain accepted g.sub.z force profiles, that is, patterns of g.sub.z force variations which represent the g.sub.z forces and onset rates to which a pilot would normally be subjected. A g force trainer should be able to reproduce such g.sub.z force patterns accurately from test to test without intervention of an operator.
Normally, in g-force trainers of the type herein the pilot is seated such that the gondola roll axis intersects the pilot's body at the elevation of the heart. As a result, as the gondola accelerates around the roll axis the pilot's head is subjected to angular rotation and centrifugal force. Applicants have recognized that this produces pilot disorientation and that this disorientation can be substantially reduced.
G-force trainers or centrifuges known to applicants utilize fixed arm counterweights to dynamically balance the arm especially at higher speeds. These counterweights are fixed to the arm such that the counterweight center of gravity is fixed relative to the trainer axis of rotation. As a result, they pose significant inertial loads, i.e., (torque) demands, on the drive motor at start-up for high onset rates. It would be desirable to preserve dynamic balance, especially at higher arm speeds, while reducing the power (torque) demands on the drive motor at start-up.
Finally, a g-force trainer should include a mechanism for protecting the pilot from injury, and the trainer components from structural damage, due to stresses arising from erratic arm motion including abrupt starts and/or stops. Arm motion of this type might result form failure or malfunction of the arm speed control.
The present invention solves all of the foregoing problems by providing an extremely lightweight yet stiff arm having a length of approximately 20 feet, a break-away shear pin which couples the arm and driven shaft, and a gondola roll axis aligned with the pilot's head at eye level thereby providing: substantially reduce pilot disorientation during acceleration or deceleration, a natural frequency in excess of 6 hz, arm deflection in the order of 1/4 inch, and an arm which can freewheel to protect the pilot from injury and the arm, yoke and gondola from structural damage. The trainer may be driven by a motor having reduced maximum horsepower output. The pilot may "execute" target tracking or missile avoidance maneuvers which affect arm motion so as to produce g.sub.z forces and onset rates representative of those which would actually be encountered by the pilot during such maneuvers. The pilot's appearance is monitored by a CCTV camera at the gondola. A computerized medical monitoring system is provided wherein physiologic data is transmitted and received with improved signal to noise ratio for accurate recordal and display.